Such implantable devices to replace an organ valve in the human and/or animal body are known from the prior art. In the past it was usual to replace particularly heart valves with an open-heart surgery, which is not an unperilous operation, especially for older patients. Thus, devices to replace a heart valve have been developed, which can be inserted without an open-heart surgery via a catheter at the desired location in the heart. For example, it is known from EP 0 592 410 to provide a compressible resilient valve, which is mounted on a resilient stent, wherein the commissural points of the elastic collapsible valve are mounted on the cylinder surface of the elastic stents. The elastic compressible valve is a biological, trilobate valve. The stent comprises a stainless steel wire folded in a number of loops and circularly bent together and welded together. The stent includes two or more closed rings that are connected to each other to form a cylindrical structure. Three of the loops in the outer ring are formed with a greater height than the other loops, to form tips at which the commissural points of the biological valve are attached. The cylindrical surface of the stent can also be closed. Due to the pipe or ring shape of the stent only a relatively poor anchorage at the implantation site, particularly in the aorta and the heart, is possible.
A more advanced anchoring for a heart valve replacement is described in DE 101 21 210 A1. According to this document, a intraluminal anchoring element is shaped differently to the cylinder shape, so that it is at least partially connected in the use position positively to the aorta. The intraluminal anchoring element of this document has therefore radially extending extensions at the exit of the heart (behind the original aortic valve). Moreover, it is curved and adapted to the curved shape of the aorta. The anchoring element is for example composed of a grid-like, loop-shaped or helical-shaped and built of a thread structure or filaments and may include several meandering, ring-forming thread structures. The individual ring-forming structures are interconnected or connected together by gluing, soldering, welding, etc. This embodiment of a heart valve replacement has the disadvantage that the anchoring element is designed very long, and thus must be placed very deep into a blood vessel or the heart. Although openings are provided for the connections to different coronary arteries, it can occur due to the length of the anchor element that they are partially covered by the anchoring element, which can result in a blockage of the blood flow or blockage of the connections to the coronary arteries.
From EP 1057460 A1 or the abstract of JP 2001/000460 A it is known, to provide a heart valve replacement device comprising a stent, wherein the stent is expandable in the radial direction of the blood vessel and a biological valve is attached to the stent. The stent valve arrangement is applied to the expanding part of a balloon catheter and inserted into the body of a human. The stent is composed of a plurality of sections, which are formed of wire. The individual wire sections are welded together. By means of the balloon catheter the stent is expanded at the implantation site to the desired diameter, which is done in two stages. After expansion of the stent at the implantation site, the diameter of the balloon catheter is reduced and the catheter is removed. The pulmonary valve replacement device remains in the pulmonary artery, touching the artery wall. A disadvantage of this heart valve replacement device is that a balloon catheter must be used to expand the stent. In addition, the stent keeps its position only due to its expanded form within the vessel or artery. However, it has been shown that this type of heart valve replacement devices suffer with problems due to shifting of the stent within the vessel, especially since, in case of a non-precise positioning, the connections to coronary arteries can be blocked, causing an at least partially closing of these connections and thus can lead to a stagnant blood flow. In addition, an incorrect positioning is problematic because using the balloon catheter, the stent can be expanded, however, cannot be reduced again in diameter.
From U.S. Pat. No. 5,855,597 it is also known to cut out star-shaped elements and assemble them to a stent. An aortic valve of a flexible, biocompatible material is inserted into a central opening of the joined star-shaped elements. Via a catheter system the stent is delivered to the desired implantation site. The star-shape achieves a fixation within the aorta, but there also exists a risk of injury, especially if the blood vessel is easily vulnerable, especially perforatable, due to age or other health conditions of the patient.
From U.S. Pat. No. 6,482,228 B1 for example an aortic valve replacement is known, with a stent and offset therefrom, but linked with it, a rotor-shaped valve replacement. This is placed over the original valve. The stent consists of several connected rings of wave-like bent wire. A disadvantage is the structure of a stent with an offset rotor-shaped aortic valve replacement for a placement behind the original aortic valve. The structure is on the one hand very complicated and on the other hand there is a risk that the rotor is disengaged from the stent. Furthermore, the rotor is positioned in the aorta and essentially secured in a longitudinal direction without a further fixation by the stent. The aortic valve replacement therefore does not provide a firm and stable unit.
As a heart valve replacement from the state of the art ring-shaped devices are known, which have post elements projecting at three points out of the ring. These can either be looped, as disclosed in WO 97/46177, or consist of a solid material, such as described in U.S. Pat. No. 4,816,029, DE 196 24 948 A1 and DE 35 41 478 A1. However, these ring-shaped valve replacement devices are all not implantable via a catheter because they cannot be collapsed to a corresponding small size.
From DE 103 34 868 a further implantable device for use in a human and/or animal body to replace an organ valve is known. The disclosed implantable device comprises a main body having a first and a second end with openings and a membrane element with at least one opening. The device has in a first operating state a large ratio of length to transverse extent along an axis and in a second operating state a smaller ratio of length to transverse extent along the axis, wherein the device can be reversely transferred by applying a force against elastic material forces from the secondary form into the primary form. Furthermore, the implantable device includes at least at one of the two ends of the main body an extending anchoring portion for anchoring the device in an organ and/or a vessel. The main body of the implantable device according to DE 103 34 868 A1 is integrally formed and for example cut out and/or punched out and/or separated out by another separation process of a single piece of material. This results in the disadvantage that the implantable device has a relatively high rigidity and must be treated chemically and/or mechanically in at least a partial region of the main body for generating different stiffnesses, and in particular etched, electro-polished, micro-grinded or otherwise treated. Furthermore, there is a risk by an excessive post-treatment of the main body, that the individual elements of the main body, in particular the struts formed therefrom, be damaged by a transfer of the implantable device from the primary form to the secondary form.
The object of the present invention is to provide an implantable device to replace an organ valve, which has a high flexibility, without the risk that the individual elements of the implantable device will be damaged by a deformation. In particular, the invention has for its object to provide an implantable device which has different stiffness in different areas.
The object is solved by an implantable device for use in the human and/or animal body to replace an organ valve, comprising a main body having a first end and a second end, wherein the first end and the second end each have an opening to provide a fluid connection through the main body between the first end and the second end; a first membrane element arranged inside or at one end of the main body, wherein the membrane element is formed in such a manner that it allows the fluid connection through the main body in a first direction and blocks the same in a second flow direction opposite the first flow direction; wherein the main body has a large ratio of length to transverse expansion along the longitudinal axis of the main body in a first operating state (primary form) and a small ratio of length to transverse expansion along the longitudinal axis of the main body in a second operating state (secondary form); and wherein the main body can be reversibly transferred from the secondary form to the primary form counter to elastic material forces by the application of a force; and wherein the main body is formed from a single wire-like element or front a plurality of wire-like elements connected to each other by means of interlocking winding and/or twisting and/or weaving in the manner of a woven and/or layered fabric and/or net.
By forming the main body of a single wire-like element or a plurality of wire-like elements connected to each other by means of interlocking winding and/or twisting and/or weaving in the manner of a woven and/or layered fabric and/or net an implantable device is created, which has a high flexibility and at the same time ensures a secure fit at the implantation side. In the secondary form the implantable device for example conforms to a vessel wall. Because of the elastic material forces a force acts in a radial direction, which secures the implantable device at the implantation site. Since the main body is reversibly transferable from a primary form into a secondary form, it can be transported to the implantation site via a catheter without any problems. At the time of leaving the catheter the implantable device unfolds from the primary form into the secondary form, whereby the diameter of the main body increases and the length is usually reduced. Because of the possibility of a reversible transfer from the primary into the secondary form and vice versa from the secondary into the primary form, in contrast to the stent according to EP 1 057 460 A1, a retrieval of the device into the catheter is possible, if during the implantation is discovered that the implantation does not orderly proceed, particularly that the implantable device is not correctly positioned to the connection to corona vessels and/or to the native heart valve and/or the aorta as well as the heart ventricle. Because of the single wire-like elements or the plurality of wire-like elements connected to each other, which forms the implantable device by means of interlocking winding and/or twisting and/or weaving in the manner of a woven and/or layered fabric and/or net the advantage results, that the inventive implantable device has a high flexibility, without the risk that single elements of the implantable device break during the transfer from the primary form into the secondary form or from the secondary form into the primary form. The single wire-like design of the implantable device, particularly of the main body, has the further advantage that no connection points, for example welding points, between single elements of the main body are present, which could break easily. Especially such a break of single elements of an implantable device can lead to sharp edges protruding out of the device, which could damage or perforate a vessel wall, particularly an aorta. The structure of the main body can be designed more uniformly by an integral embodiment as it is possible in case of connecting separate ring-like elements, as known from the prior art. An implantable device built by a plurality of wire-like elements connected to each other has the advantage, that the implantable device can be easily manufactured automatically.
In a variant of the invention the implantable device is formed stent-like, wherein the first end and/or the second end is folded on each other to a double-layer in the second operating state (secondary form). Because of the double-layer the force acting in the radial direction during the transfer from the primary form into the secondary form is increased, whereby the fixing of the implantable device at the implantation site is improved, without a negative impact on the inner diameter (gate-way) of the implantable device. According to an advantageous variant the double-layer of the first end and/or the second end is formed by a backfolding into the implantable device and/or outwardly onto the implantable device.
Pursuant to a variant of the invention the main body has in the second operating state (secondary form) at the first end and/or second end at least one radially outwardly of the main body extending anchoring member for anchoring the device in an organ and/or in a vessel. Thereby an implantable device to replace an organ valve is created, which has, due to the use of at least one radially outwardly extending anchoring element at one end of the main body, a particular well fixing in the vessel and/or organ. In case of using the implantable device as a heart valve replacement the one end with the radially outwardly extending anchoring element can for example extend into the left ventricle and adhere there, and the other end of the main body can confirm to the wall of the aorta. Thereby the implantable device or the main body can be built much shorter than for example possible with a stent according to DE 101 21 210 A1.